Stainless steel is the default "safe" answer for non-toxic cookware. No coating to wear out, no PFAS, induction-compatible, lasts decades. We sell it on this site and we cook with it ourselves. The science is also more nuanced than a flat thumbs-up.
A 2013 Oregon State University paper (Kamerud, Hobbie, and Anderson in J. Agric. Food Chem.) measured what happens when tomato sauce simmers for hours in eight different stainless steel pans. Even after a pan had been used for ten cooking cycles — meaning most of the initial leaching had stabilized — a 126 g serving still contained an average of 88 μg of nickel and 86 μg of chromium. For most healthy adults that is a non-issue. For the estimated 17% of women and 3% of men in the US with nickel allergy, it is worth understanding before you commit to a six-hour Sunday gravy.
This is the evidence-based version of the story. Not "stainless is toxic" — it isn't — but "here is what the chemistry actually does, and here is who should care."
A short stainless steel chemistry primer
Stainless steel is iron alloyed with two elements that change how it behaves at the cooking surface:
- Chromium (typically 16-18%) — forms a passive oxide layer that makes the steel corrosion-resistant. This is the "stainless" part.
- Nickel (variable) — stabilizes the austenitic crystal structure, which is what gives premium stainless its non-magnetic shine and ductility.
The grade tells you the ratio. The three you will see on cookware boxes:
- 304 stainless (often labeled 18/8) — approximately 18% chromium and 8% nickel. The most common cooking-surface grade. Used in Made In, Cuisinart MultiClad Pro, and most other home stainless cookware.
- 316 stainless (often labeled 18/10) — roughly 16-18% chromium, 10% nickel, plus 2-3% molybdenum for corrosion resistance against chlorides. Used in Demeyere Industry 5 and many European brands. Heritage Steel's Titanium Series uses 316Ti, a titanium-stabilized 316.
- 18/0 (AISI 430) — approximately 18% chromium and effectively 0% nickel. Ferritic (magnetic), more common in flatware than cookware.
What the Kamerud 2013 study actually found
The Oregon State team tested eight stainless saucepans across grades by simmering tomato sauce for 2, 4, 6, and 20 hours, then measuring nickel and chromium concentrations in the sauce.
Three findings worth knowing:
- Leaching is real and acid-driven. After 6 hours of simmering, nickel concentrations rose up to 26-fold and chromium up to 7-fold compared to sauce cooked in glass. The longest cooks pushed nickel up to a 34-fold increase.
- New pans leach the most; the curve flattens after about six cycles. The first pot of sauce in a brand-new 316 pan delivered roughly 747 μg of nickel per 126 g serving. By the tenth cycle the same pan delivered closer to 88 μg.
- 316 leached more nickel than 304. Higher nickel content in the alloy translated to higher nickel transfer into the food.
This is the raw data. What it means depends on what you compare it against.
Putting 88 μg in context
Adult dietary nickel intake from food sits in the 220-350 μg/day range for typical mixed diets, with higher numbers in people who eat more legumes, oats, nuts, soy, and chocolate (all naturally nickel-rich). An 88 μg contribution from a single serving of slow-simmered tomato sauce in a broken-in stainless pan is meaningful — about a quarter to a third of a typical day's intake — but it is not a dose that, on its own, exceeds the EFSA 2020 tolerable daily intake of 13 μg/kg body weight per day (which works out to roughly 910 μg for a 70 kg adult).
For a healthy adult with no nickel sensitivity, that math is reassuring: even a generous serving from a long simmer leaves a lot of headroom under the TDI.
For someone with diagnosed nickel allergy, the picture changes. A 2006 review by Jensen and colleagues documented dose-dependent flare reactions in nickel-sensitive subjects at single oral doses of 0.3 mg, 1 mg, and 4 mg of nickel sulfate. The 88 μg per serving from a broken-in stainless pan is well below those provocative thresholds — but multiple servings, plus dietary nickel from oats and chocolate, can stack closer to a flare-relevant range for the most sensitive subgroup.
Who actually needs to care
The honest answer is "a smaller group than the internet claims, and a larger group than a flat dismissal would suggest."
Nickel allergy affects roughly 17% of women and 3% of men in the United States, with North American Contact Dermatitis Group patch test data showing average sensitivity around 17.5%. Most of those people experience contact dermatitis from skin exposure (jewelry, watch backs, belt buckles) — not systemic flares from food. A smaller subset develops systemic contact dermatitis from oral nickel and benefits from a low-nickel diet.
If you have:
- A diagnosed nickel allergy with confirmed systemic flares from food
- Recurring eczema or dyshidrotic eczema unresponsive to standard treatment
- A dermatologist or allergist who has specifically recommended dietary nickel restriction
…then the cookware grade matters. Talk to your clinician before changing what you cook in.
For everyone else — including the "I think I might be allergic, my earrings turn my skin green" group — stainless is fine. A skin-only nickel sensitivity does not automatically translate to a food sensitivity, and self-diagnosing is a fast path to over-restricting your diet for no benefit.
Practical recommendations
For most cooks, Made In Stainless Clad, Demeyere Industry 5, and Cuisinart MultiClad Pro are all reasonable picks. The leaching the Kamerud study measured is real but small relative to total dietary intake, and the trade-offs against PTFE-coated alternatives still favor stainless.
For someone with diagnosed nickel allergy, the conservative options are:
- Cast iron — Lodge 12-inch skillet is just iron and seasoning oil. No nickel.
- Enameled cast iron — vitreous enamel is glass fused to iron. Inert to acidic foods, no nickel.
- 18/0 (AISI 430) stainless when you can find it — most common in flatware, less common in cookware bodies.
A note on Heritage Steel Titanium: the brand's marketing emphasizes lower metal leaching from the 316Ti cooking surface. Heritage Steel themselves acknowledge nickel is part of the alloy — it is not a nickel-free pan. The case for it for nickel-sensitive cooks is "lower-leaching premium stainless," not "nickel-free." For confirmed nickel allergy, cast iron is the cleaner answer.
General hygiene for any stainless pan:
- Don't simmer tomato sauce for 6+ hours in a brand-new stainless pan. The first few cycles leach the most.
- Acidic short cooks (deglazing, finishing a sauce) are not a concern.
- If you want to cook a long marinara, a Lodge cast iron Dutch oven or an enameled cast iron one is the right tool — for any cook, not just nickel-sensitive ones.
What this changes about the broader stainless story
It does not change the comparison to PTFE non-stick. Both stainless and cast iron are PFAS-free options — the leaching question is a separate axis. The 88 μg per serving of nickel from a broken-in stainless pan is a different category of exposure than what fluoropolymer chemistry contributes when a non-stick pan is overheated.
It does add nuance to "stainless is the safest cookware." It is the safest for most people. For the ~17% of women and ~3% of men with nickel sensitivity, the answer is "depends what you cook in it, and for how long." For the smaller subset with diagnosed systemic nickel reactions, the answer is "talk to your allergist and consider cast iron."
That distinction is the whole reason to read the research instead of the marketing copy.
